1. Field of the Invention
The present invention relates to a disposable container for dispensing a liquid medication or medicament and, more particularly, to a relatively inexpensive disposable container with or without liquid medication, e.g., liquid artificial tears, contained therein, which can maintain the sterility of a sterile liquid medication contained therein without the necessity of a preservative being present in said liquid medication, either prior to packaging or subsequently.
2. Description of Related Art
Patient medications are frequently prescribed which are to be dispensed in a metered amount over a predetermined time period. Thus, the medication is prepared and marketed in a predetermined quantity adapted for a predetermined number of individual self-administerable dosages, and the patient usually self-administers the medication over a period of days. A common utilization of such dispensers is in the field of ophthalmology, wherein various forms of medication are frequently prescribed for the patient to be dispensed in metered drops from a disposable container. Examples of such medication can be decongestants, antibiotics, anti-inflammatories, antiglaucoma medication, antibacterials, anesthetics, mydriatics, anticholinergics, and miotics, as well as combinations thereof. Frequently such medication requires the addition of an antibacterial agent such as benzalkonium chloride, thimerosal, chlorobutanol, zepazonium, other quaternary ammonium compound, or other bacteriostatic or bactericidal agent. Such agents are frequently necessary to preserve the sterility of the medication during the period in which it is stored in the dispensing container. However, such antibacterial agents also frequently contribute to, or are solely responsible for, the stinging effect perceived by a patient when self-administering the drops. Thus, the actual prescribed therapeutic medication may not itself create an unpleasant sensation in the eye of a user, but the preservative therein will frequently contribute to or independently cause such effect.
Numerous examples of attempts to maintain the sterility of either a liquid to be dispensed or a liquid to be collected are of record in the medical field. For example, U.S. Pat. No. 4,664,800 discloses a filter device for use with intravenous drip chambers.
U.S Pat. No. 3,951,798 discloses a dispenser device provided with a filter member capable of separating fibrin and particulate material from blood serum, and for dispensing small amounts of the filtered serum. The filter is temporarily retained within the cap. After the fluid to be filtered and dispensed is placed within the container, the cap and filter assembly is screwed over the mouth of the container, which forces the filter into place. Subsequently, the filter maintains the particulate material within the dispensing bottle.
U.S. Pat. No. 3,592,245 discloses a dispensing package for medicaments which are to be dissolved in a parenteral solution container prior to use. A membrane filter is disposed between the container and the cap and serves the purpose of removing particulate material which may have solidified from the solution during the shelflife of the product.
The following patents are cited of general interest as disclosing various forms of filtration systems, alone or in combination with storage containers: U.S. Pat. Nos. 920,791, 3,722,694, 3,954,623, 4,136,036, 4,190,542, 4,234,095, and 4,435,289.
Microgon, Inc. of Laguna Hills, Calif., has marketed a series of filter products which incorporate hollow tubular filter membranes or members in modules for small volume sterile filtration purposes, and for syringe filters, to accommodate the aspiration or injection of fluids into vials, ampules, test tubes, and other vessels.
The prior art is still seeking a relatively inexpensive disposable fluid medication container which can maintain a sterile environment for liquid medication contained or to be contained therein without the necessity of added preservative.